The present invention relates to a obturator valve and a device for coupling pipes in which at least a first pipe to be coupled is provided at one end with a obturator valve.
In this type of device, it is known to drive in rotation a obturator arranged in the valve, the obturator could have the form of a disc or a sphere, setting the obturator in rotation making the valve correspond to an open position, enabling the fluid to go through, or to a closed position. As an example, when the obturator is a sphere, a flow channel is arranged inside the sphere, and in the open position of the valve, the flow channel enables the fluid to go through on the axis of the valve, whereas in the closed position, the flow channel is oriented across the fluid passage, and blocks the latter.
The obturator rests, in a known manner, on a seat formed in the body of the valve. This contact allows the valve to be sealed, and it is known to keep this contact constant, no matter the position of the valve, open or closed, on the one hand by the pressure of the fluid coming against the obturator, and on the other hand, by the pressure exerted continuously by a pre-loading spring. Sealing is thus provided at both strong and low fluid pressures, the force of the pre-loading spring replacing the fluid pressure in the latter case. Such a provision has however the drawback, which is to require a substantial coupling, when the obturator is being set into rotation, to tear said obturator away from the seat. This can cause the obturator or the seat to wear off more quickly, depending on the materials used for one and the other.
The device disclosed in the document EP0564564 also has this drawback. In this document, a sphere has a flat sealing surface, substantially coplanar to the end coupling plane of the valve. The purpose of this document is for the ball to not extend outside of the valve chamber when the sphere rotates. To this end, a cam is arranged on the sphere and cooperates with a cam structure arranged inside the valve chamber. It is the rotation of the sphere which causes the cam to move along the cam surface. The sphere therefore starts rotating before the action of the cam, the rotation causing the translational motion. At the time the rotation is starting, the sphere is therefore invariably pre-loadingly supported against the seat, and the previously mentioned drawbacks arise.